Around the world in a solar car

The 36-year-old Swiss school teacher pulled up to the U.N. climate talks in Poznan, Poland, where representatives from almost 200 countries hope to hammer out a new treaty to address climate change.

Palmer didn't burn any petrol during his round the world drive, and says the car "ran like a Swiss watch," proving solar is a viable transportation technology.

"These new technologies are ready," said Palmer. "The car is ecological, economical and absolutely reliable."

The three-wheeled "Solar Taxi" can reach 55mph and has a range of 185 miles. It seats two people comfortably and saw just two breakdowns during the trip. Palmer offered rides to thousands of people, including U.N. Secretary General Ban Ki-moon and New York Mayor Michael Bloomberg, along the way to promote solar power and raise awareness about global warming.

Swiss scientists worked with Palmer to build the three-wheeler. It's driven by an electric motor powered by a molten salt battery charged by a solar array hauled on a trailer (a cord plugged into a wall outlet). The car weighs 1100 pounds and is made of aluminium and fibreglass to maximise performance.

Palmer told the BBC the Solar Taxi cost "as much as two Ferraris" to build, but he estimates that it could be mass-produced for about £8820, although the solar panels would cost another four grand. Still, that isn't much less than the next-generation Honda Insight will go for.

That prompted Palmer to challenge the auto industry to develop a solar car.

"People love this idea of a solar car," he said outside the U.N. climate talks. "I hope that the car industry hears ... and makes electric cars in the future."

Next year Palmer plans to go around the world in 80 days in six alt-fuel vehicles that draw power from renewable sources like hydro, geothermal and wind.